chore: ruff auto-fix PLR6201 resweep — tuple → set in membership tests (#27355)

Six days after #23937 (608 fixes) the codebase had accumulated 241 new
PLR6201 violations. Same mechanical `x in (...)` → `x in {...}` fix,
same zero-risk profile: set lookup is O(1) vs O(n) for tuple and the
two are semantically equivalent for hashable scalar membership tests.

All 241 instances fixed via `ruff check --select PLR6201 --fix
--unsafe-fixes`, zero remaining. Every changed value is a hashable
scalar (str/int/None/enum/signal); no risk of unhashable runtime
errors. No behavior change.

Test plan:
- 119 files changed, +244/-244 (net zero) — exactly one-line edits
- `ruff check` clean afterward
- Compile checks pass on the largest touched files (cli.py, run_agent.py,
  gateway/run.py, gateway/platforms/discord.py, model_tools.py)
- Subset broad test run on tests/gateway/ tests/hermes_cli/ tests/agent/
  tests/tools/: 18187 passed, 59 pre-existing failures (verified against
  origin/main with the same shape — identical failure count, identical
  category — all xdist test-order flakes unrelated to this change)

Follows the same template as PR #23937 ([tracker: #23972](https://github.com/NousResearch/hermes-agent/issues/23972)).

plugins/memory/honcho/client.py

@@ -47,7 +47,7 @@ def resolve_active_host() -> str:
     try:
         from hermes_cli.profiles import get_active_profile_name
         profile = get_active_profile_name()
-        if profile and profile not in ("default", "custom"):
+        if profile and profile not in {"default", "custom"}:
             return f"{HOST}.{profile}"
     except Exception:
         pass
@@ -653,7 +653,7 @@ class HonchoClientConfig:
             return base
 
         # per-directory: one Honcho session per working directory (default)
-        if self.session_strategy in ("per-directory", "per-session"):
+        if self.session_strategy in {"per-directory", "per-session"}:
             base = Path(cwd).name
             if self.session_peer_prefix and self.peer_name:
                 return f"{self.peer_name}-{base}"